net/ipv6/xfrm6_tunnel.c

   1 /*
   2  * Copyright (C)2003,2004 USAGI/WIDE Project
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  17  *
  18  * Authors      Mitsuru KANDA  <mk@linux-ipv6.org>
  19  *              YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
  20  *
  21  * Based on net/ipv4/xfrm4_tunnel.c
  22  *
  23  */
  24 #include <linux/module.h>
  25 #include <linux/xfrm.h>
  26 #include <linux/list.h>
  27 #include <net/ip.h>
  28 #include <net/xfrm.h>
  29 #include <net/ipv6.h>
  30 #include <linux/ipv6.h>
  31 #include <linux/icmpv6.h>
  32 #include <linux/mutex.h>
  33
  34 #ifdef CONFIG_IPV6_XFRM6_TUNNEL_DEBUG
  35 # define X6TDEBUG       3
  36 #else
  37 # define X6TDEBUG       1
  38 #endif
  39
  40 #define X6TPRINTK(fmt, args...)         printk(fmt, ## args)
  41 #define X6TNOPRINTK(fmt, args...)       do { ; } while(0)
  42
  43 #if X6TDEBUG >= 1
  44 # define X6TPRINTK1     X6TPRINTK
  45 #else
  46 # define X6TPRINTK1     X6TNOPRINTK
  47 #endif
  48
  49 #if X6TDEBUG >= 3
  50 # define X6TPRINTK3     X6TPRINTK
  51 #else
  52 # define X6TPRINTK3     X6TNOPRINTK
  53 #endif
  54
  55 /*
  56  * xfrm_tunnel_spi things are for allocating unique id ("spi")
  57  * per xfrm_address_t.
  58  */
  59 struct xfrm6_tunnel_spi {
  60         struct hlist_node list_byaddr;
  61         struct hlist_node list_byspi;
  62         xfrm_address_t addr;
  63         u32 spi;
  64         atomic_t refcnt;
  65 #ifdef XFRM6_TUNNEL_SPI_MAGIC
  66         u32 magic;
  67 #endif
  68 };
  69
  70 #ifdef CONFIG_IPV6_XFRM6_TUNNEL_DEBUG
  71 # define XFRM6_TUNNEL_SPI_MAGIC 0xdeadbeef
  72 #endif
  73
  74 static DEFINE_RWLOCK(xfrm6_tunnel_spi_lock);
  75
  76 static u32 xfrm6_tunnel_spi;
  77
  78 #define XFRM6_TUNNEL_SPI_MIN    1
  79 #define XFRM6_TUNNEL_SPI_MAX    0xffffffff
  80
  81 static kmem_cache_t *xfrm6_tunnel_spi_kmem __read_mostly;
  82
  83 #define XFRM6_TUNNEL_SPI_BYADDR_HSIZE 256
  84 #define XFRM6_TUNNEL_SPI_BYSPI_HSIZE 256
  85
  86 static struct hlist_head xfrm6_tunnel_spi_byaddr[XFRM6_TUNNEL_SPI_BYADDR_HSIZE];
  87 static struct hlist_head xfrm6_tunnel_spi_byspi[XFRM6_TUNNEL_SPI_BYSPI_HSIZE];
  88
  89 #ifdef XFRM6_TUNNEL_SPI_MAGIC
  90 static int x6spi_check_magic(const struct xfrm6_tunnel_spi *x6spi,
  91                              const char *name)
  92 {
  93         if (unlikely(x6spi->magic != XFRM6_TUNNEL_SPI_MAGIC)) {
  94                 X6TPRINTK3(KERN_DEBUG "%s(): x6spi object "
  95                                       "at %p has corrupted magic %08x "
  96                                       "(should be %08x)\n",
  97                            name, x6spi, x6spi->magic, XFRM6_TUNNEL_SPI_MAGIC);
  98                 return -1;
  99         }
 100         return 0;
 101 }
 102 #else
 103 static int inline x6spi_check_magic(const struct xfrm6_tunnel_spi *x6spi,
 104                                     const char *name)
 105 {
 106         return 0;
 107 }
 108 #endif
 109
 110 #define X6SPI_CHECK_MAGIC(x6spi) x6spi_check_magic((x6spi), __FUNCTION__)
 111
 112
 113 static unsigned inline xfrm6_tunnel_spi_hash_byaddr(xfrm_address_t *addr)
 114 {
 115         unsigned h;
 116
 117         X6TPRINTK3(KERN_DEBUG "%s(addr=%p)\n", __FUNCTION__, addr);
 118
 119         h = addr->a6[0] ^ addr->a6[1] ^ addr->a6[2] ^ addr->a6[3];
 120         h ^= h >> 16;
 121         h ^= h >> 8;
 122         h &= XFRM6_TUNNEL_SPI_BYADDR_HSIZE - 1;
 123
 124         X6TPRINTK3(KERN_DEBUG "%s() = %u\n", __FUNCTION__, h);
 125
 126         return h;
 127 }
 128
 129 static unsigned inline xfrm6_tunnel_spi_hash_byspi(u32 spi)
 130 {
 131         return spi % XFRM6_TUNNEL_SPI_BYSPI_HSIZE;
 132 }
 133
 134
 135 static int xfrm6_tunnel_spi_init(void)
 136 {
 137         int i;
 138
 139         X6TPRINTK3(KERN_DEBUG "%s()\n", __FUNCTION__);
 140
 141         xfrm6_tunnel_spi = 0;
 142         xfrm6_tunnel_spi_kmem = kmem_cache_create("xfrm6_tunnel_spi",
 143                                                   sizeof(struct xfrm6_tunnel_spi),
 144                                                   0, SLAB_HWCACHE_ALIGN,
 145                                                   NULL, NULL);
 146         if (!xfrm6_tunnel_spi_kmem) {
 147                 X6TPRINTK1(KERN_ERR
 148                            "%s(): failed to allocate xfrm6_tunnel_spi_kmem\n",
 149                            __FUNCTION__);
 150                 return -ENOMEM;
 151         }
 152
 153         for (i = 0; i < XFRM6_TUNNEL_SPI_BYADDR_HSIZE; i++)
 154                 INIT_HLIST_HEAD(&xfrm6_tunnel_spi_byaddr[i]);
 155         for (i = 0; i < XFRM6_TUNNEL_SPI_BYSPI_HSIZE; i++)
 156                 INIT_HLIST_HEAD(&xfrm6_tunnel_spi_byspi[i]);
 157         return 0;
 158 }
 159
 160 static void xfrm6_tunnel_spi_fini(void)
 161 {
 162         int i;
 163
 164         X6TPRINTK3(KERN_DEBUG "%s()\n", __FUNCTION__);
 165
 166         for (i = 0; i < XFRM6_TUNNEL_SPI_BYADDR_HSIZE; i++) {
 167                 if (!hlist_empty(&xfrm6_tunnel_spi_byaddr[i]))
 168                         goto err;
 169         }
 170         for (i = 0; i < XFRM6_TUNNEL_SPI_BYSPI_HSIZE; i++) {
 171                 if (!hlist_empty(&xfrm6_tunnel_spi_byspi[i]))
 172                         goto err;
 173         }
 174         kmem_cache_destroy(xfrm6_tunnel_spi_kmem);
 175         xfrm6_tunnel_spi_kmem = NULL;
 176         return;
 177 err:
 178         X6TPRINTK1(KERN_ERR "%s(): table is not empty\n", __FUNCTION__);
 179         return;
 180 }
 181
 182 static struct xfrm6_tunnel_spi *__xfrm6_tunnel_spi_lookup(xfrm_address_t *saddr)
 183 {
 184         struct xfrm6_tunnel_spi *x6spi;
 185         struct hlist_node *pos;
 186
 187         X6TPRINTK3(KERN_DEBUG "%s(saddr=%p)\n", __FUNCTION__, saddr);
 188
 189         hlist_for_each_entry(x6spi, pos,
 190                              &xfrm6_tunnel_spi_byaddr[xfrm6_tunnel_spi_hash_byaddr(saddr)],
 191                              list_byaddr) {
 192                 if (memcmp(&x6spi->addr, saddr, sizeof(x6spi->addr)) == 0) {
 193                         X6SPI_CHECK_MAGIC(x6spi);
 194                         X6TPRINTK3(KERN_DEBUG "%s() = %p(%u)\n", __FUNCTION__, x6spi, x6spi->spi);
 195                         return x6spi;
 196                 }
 197         }
 198
 199         X6TPRINTK3(KERN_DEBUG "%s() = NULL(0)\n", __FUNCTION__);
 200         return NULL;
 201 }
 202
 203 u32 xfrm6_tunnel_spi_lookup(xfrm_address_t *saddr)
 204 {
 205         struct xfrm6_tunnel_spi *x6spi;
 206         u32 spi;
 207
 208         X6TPRINTK3(KERN_DEBUG "%s(saddr=%p)\n", __FUNCTION__, saddr);
 209
 210         read_lock_bh(&xfrm6_tunnel_spi_lock);
 211         x6spi = __xfrm6_tunnel_spi_lookup(saddr);
 212         spi = x6spi ? x6spi->spi : 0;
 213         read_unlock_bh(&xfrm6_tunnel_spi_lock);
 214         return spi;
 215 }
 216
 217 EXPORT_SYMBOL(xfrm6_tunnel_spi_lookup);
 218
 219 static u32 __xfrm6_tunnel_alloc_spi(xfrm_address_t *saddr)
 220 {
 221         u32 spi;
 222         struct xfrm6_tunnel_spi *x6spi;
 223         struct hlist_node *pos;
 224         unsigned index;
 225
 226         X6TPRINTK3(KERN_DEBUG "%s(saddr=%p)\n", __FUNCTION__, saddr);
 227
 228         if (xfrm6_tunnel_spi < XFRM6_TUNNEL_SPI_MIN ||
 229             xfrm6_tunnel_spi >= XFRM6_TUNNEL_SPI_MAX)
 230                 xfrm6_tunnel_spi = XFRM6_TUNNEL_SPI_MIN;
 231         else
 232                 xfrm6_tunnel_spi++;
 233
 234         for (spi = xfrm6_tunnel_spi; spi <= XFRM6_TUNNEL_SPI_MAX; spi++) {
 235                 index = xfrm6_tunnel_spi_hash_byspi(spi);
 236                 hlist_for_each_entry(x6spi, pos,
 237                                      &xfrm6_tunnel_spi_byspi[index],
 238                                      list_byspi) {
 239                         if (x6spi->spi == spi)
 240                                 goto try_next_1;
 241                 }
 242                 xfrm6_tunnel_spi = spi;
 243                 goto alloc_spi;
 244 try_next_1:;
 245         }
 246         for (spi = XFRM6_TUNNEL_SPI_MIN; spi < xfrm6_tunnel_spi; spi++) {
 247                 index = xfrm6_tunnel_spi_hash_byspi(spi);
 248                 hlist_for_each_entry(x6spi, pos,
 249                                      &xfrm6_tunnel_spi_byspi[index],
 250                                      list_byspi) {
 251                         if (x6spi->spi == spi)
 252                                 goto try_next_2;
 253                 }
 254                 xfrm6_tunnel_spi = spi;
 255                 goto alloc_spi;
 256 try_next_2:;
 257         }
 258         spi = 0;
 259         goto out;
 260 alloc_spi:
 261         X6TPRINTK3(KERN_DEBUG "%s(): allocate new spi for " NIP6_FMT "\n",
 262                               __FUNCTION__,
 263                               NIP6(*(struct in6_addr *)saddr));
 264         x6spi = kmem_cache_alloc(xfrm6_tunnel_spi_kmem, SLAB_ATOMIC);
 265         if (!x6spi) {
 266                 X6TPRINTK1(KERN_ERR "%s(): kmem_cache_alloc() failed\n",
 267                            __FUNCTION__);
 268                 goto out;
 269         }
 270 #ifdef XFRM6_TUNNEL_SPI_MAGIC
 271         x6spi->magic = XFRM6_TUNNEL_SPI_MAGIC;
 272 #endif
 273         memcpy(&x6spi->addr, saddr, sizeof(x6spi->addr));
 274         x6spi->spi = spi;
 275         atomic_set(&x6spi->refcnt, 1);
 276
 277         hlist_add_head(&x6spi->list_byspi, &xfrm6_tunnel_spi_byspi[index]);
 278
 279         index = xfrm6_tunnel_spi_hash_byaddr(saddr);
 280         hlist_add_head(&x6spi->list_byaddr, &xfrm6_tunnel_spi_byaddr[index]);
 281         X6SPI_CHECK_MAGIC(x6spi);
 282 out:
 283         X6TPRINTK3(KERN_DEBUG "%s() = %u\n", __FUNCTION__, spi);
 284         return spi;
 285 }
 286
 287 u32 xfrm6_tunnel_alloc_spi(xfrm_address_t *saddr)
 288 {
 289         struct xfrm6_tunnel_spi *x6spi;
 290         u32 spi;
 291
 292         X6TPRINTK3(KERN_DEBUG "%s(saddr=%p)\n", __FUNCTION__, saddr);
 293
 294         write_lock_bh(&xfrm6_tunnel_spi_lock);
 295         x6spi = __xfrm6_tunnel_spi_lookup(saddr);
 296         if (x6spi) {
 297                 atomic_inc(&x6spi->refcnt);
 298                 spi = x6spi->spi;
 299         } else
 300                 spi = __xfrm6_tunnel_alloc_spi(saddr);
 301         write_unlock_bh(&xfrm6_tunnel_spi_lock);
 302
 303         X6TPRINTK3(KERN_DEBUG "%s() = %u\n", __FUNCTION__, spi);
 304
 305         return spi;
 306 }
 307
 308 EXPORT_SYMBOL(xfrm6_tunnel_alloc_spi);
 309
 310 void xfrm6_tunnel_free_spi(xfrm_address_t *saddr)
 311 {
 312         struct xfrm6_tunnel_spi *x6spi;
 313         struct hlist_node *pos, *n;
 314
 315         X6TPRINTK3(KERN_DEBUG "%s(saddr=%p)\n", __FUNCTION__, saddr);
 316
 317         write_lock_bh(&xfrm6_tunnel_spi_lock);
 318
 319         hlist_for_each_entry_safe(x6spi, pos, n,
 320                                   &xfrm6_tunnel_spi_byaddr[xfrm6_tunnel_spi_hash_byaddr(saddr)],
 321                                   list_byaddr)
 322         {
 323                 if (memcmp(&x6spi->addr, saddr, sizeof(x6spi->addr)) == 0) {
 324                         X6TPRINTK3(KERN_DEBUG "%s(): x6spi object for " NIP6_FMT
 325                                               " found at %p\n",
 326                                    __FUNCTION__,
 327                                    NIP6(*(struct in6_addr *)saddr),
 328                                    x6spi);
 329                         X6SPI_CHECK_MAGIC(x6spi);
 330                         if (atomic_dec_and_test(&x6spi->refcnt)) {
 331                                 hlist_del(&x6spi->list_byaddr);
 332                                 hlist_del(&x6spi->list_byspi);
 333                                 kmem_cache_free(xfrm6_tunnel_spi_kmem, x6spi);
 334                                 break;
 335                         }
 336                 }
 337         }
 338         write_unlock_bh(&xfrm6_tunnel_spi_lock);
 339 }
 340
 341 EXPORT_SYMBOL(xfrm6_tunnel_free_spi);
 342
 343 static int xfrm6_tunnel_output(struct xfrm_state *x, struct sk_buff *skb)
 344 {
 345         struct ipv6hdr *top_iph;
 346
 347         top_iph = (struct ipv6hdr *)skb->data;
 348         top_iph->payload_len = htons(skb->len - sizeof(struct ipv6hdr));
 349
 350         return 0;
 351 }
 352
 353 static int xfrm6_tunnel_input(struct xfrm_state *x, struct sk_buff *skb)
 354 {
 355         return 0;
 356 }
 357
 358 static int xfrm6_tunnel_rcv(struct sk_buff *skb)
 359 {
 360         struct ipv6hdr *iph = skb->nh.ipv6h;
 361         u32 spi;
 362
 363         spi = xfrm6_tunnel_spi_lookup((xfrm_address_t *)&iph->saddr);
 364         return xfrm6_rcv_spi(skb, spi);
 365 }
 366
 367 static int xfrm6_tunnel_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 368                             int type, int code, int offset, __u32 info)
 369 {
 370         /* xfrm6_tunnel native err handling */
 371         switch (type) {
 372         case ICMPV6_DEST_UNREACH:
 373                 switch (code) {
 374                 case ICMPV6_NOROUTE:
 375                 case ICMPV6_ADM_PROHIBITED:
 376                 case ICMPV6_NOT_NEIGHBOUR:
 377                 case ICMPV6_ADDR_UNREACH:
 378                 case ICMPV6_PORT_UNREACH:
 379                 default:
 380                         X6TPRINTK3(KERN_DEBUG
 381                                    "xfrm6_tunnel: Destination Unreach.\n");
 382                         break;
 383                 }
 384                 break;
 385         case ICMPV6_PKT_TOOBIG:
 386                         X6TPRINTK3(KERN_DEBUG
 387                                    "xfrm6_tunnel: Packet Too Big.\n");
 388                 break;
 389         case ICMPV6_TIME_EXCEED:
 390                 switch (code) {
 391                 case ICMPV6_EXC_HOPLIMIT:
 392                         X6TPRINTK3(KERN_DEBUG
 393                                    "xfrm6_tunnel: Too small Hoplimit.\n");
 394                         break;
 395                 case ICMPV6_EXC_FRAGTIME:
 396                 default:
 397                         break;
 398                 }
 399                 break;
 400         case ICMPV6_PARAMPROB:
 401                 switch (code) {
 402                 case ICMPV6_HDR_FIELD: break;
 403                 case ICMPV6_UNK_NEXTHDR: break;
 404                 case ICMPV6_UNK_OPTION: break;
 405                 }
 406                 break;
 407         default:
 408                 break;
 409         }
 410
 411         return 0;
 412 }
 413
 414 static int xfrm6_tunnel_init_state(struct xfrm_state *x)
 415 {
 416         if (!x->props.mode)
 417                 return -EINVAL;
 418
 419         if (x->encap)
 420                 return -EINVAL;
 421
 422         x->props.header_len = sizeof(struct ipv6hdr);
 423
 424         return 0;
 425 }
 426
 427 static void xfrm6_tunnel_destroy(struct xfrm_state *x)
 428 {
 429         xfrm6_tunnel_free_spi((xfrm_address_t *)&x->props.saddr);
 430 }
 431
 432 static struct xfrm_type xfrm6_tunnel_type = {
 433         .description    = "IP6IP6",
 434         .owner          = THIS_MODULE,
 435         .proto          = IPPROTO_IPV6,
 436         .init_state     = xfrm6_tunnel_init_state,
 437         .destructor     = xfrm6_tunnel_destroy,
 438         .input          = xfrm6_tunnel_input,
 439         .output         = xfrm6_tunnel_output,
 440 };
 441
 442 static struct xfrm6_tunnel xfrm6_tunnel_handler = {
 443         .handler        = xfrm6_tunnel_rcv,
 444         .err_handler    = xfrm6_tunnel_err,
 445         .priority       = 2,
 446 };
 447
 448 static int __init xfrm6_tunnel_init(void)
 449 {
 450         X6TPRINTK3(KERN_DEBUG "%s()\n", __FUNCTION__);
 451
 452         if (xfrm_register_type(&xfrm6_tunnel_type, AF_INET6) < 0) {
 453                 X6TPRINTK1(KERN_ERR
 454                            "xfrm6_tunnel init: can't add xfrm type\n");
 455                 return -EAGAIN;
 456         }
 457         if (xfrm6_tunnel_register(&xfrm6_tunnel_handler)) {
 458                 X6TPRINTK1(KERN_ERR
 459                            "xfrm6_tunnel init(): can't add handler\n");
 460                 xfrm_unregister_type(&xfrm6_tunnel_type, AF_INET6);
 461                 return -EAGAIN;
 462         }
 463         if (xfrm6_tunnel_spi_init() < 0) {
 464                 X6TPRINTK1(KERN_ERR
 465                            "xfrm6_tunnel init: failed to initialize spi\n");
 466                 xfrm6_tunnel_deregister(&xfrm6_tunnel_handler);
 467                 xfrm_unregister_type(&xfrm6_tunnel_type, AF_INET6);
 468                 return -EAGAIN;
 469         }
 470         return 0;
 471 }
 472
 473 static void __exit xfrm6_tunnel_fini(void)
 474 {
 475         X6TPRINTK3(KERN_DEBUG "%s()\n", __FUNCTION__);
 476
 477         xfrm6_tunnel_spi_fini();
 478         if (xfrm6_tunnel_deregister(&xfrm6_tunnel_handler))
 479                 X6TPRINTK1(KERN_ERR
 480                            "xfrm6_tunnel close: can't remove handler\n");
 481         if (xfrm_unregister_type(&xfrm6_tunnel_type, AF_INET6) < 0)
 482                 X6TPRINTK1(KERN_ERR
 483                            "xfrm6_tunnel close: can't remove xfrm type\n");
 484 }
 485
 486 module_init(xfrm6_tunnel_init);
 487 module_exit(xfrm6_tunnel_fini);
 488 MODULE_LICENSE("GPL");